Electric safety lamp



J. BECKMANN ELECTRIC SAFETY LAMP June 24, 1930.

Filed Aug. 27, 1928 livel 7//////// siii.: 252.15%/

Patented, June24, 193e UNITED STATES JOHANNES BECKMANN, OFQAIQTQNA, o'r'rENsErL enniyrnNY Application mea Augustev, 192s, serial No. 302,262, ,again Germany :runes/i; 1e2e'.. Y

' Electric lamps for lighting spacesior containers filled with explosive gases require special attention in order that the explosive gas is not ignited by a contact spark vat the switching in of. a circuitfor the glow lamp lbulb. A condition for Ya lamp of this type working with absolute reliability is, to have Y a vpermanent control that all elements inthe lamp are in order and packed against the if outer air, so that no explosive gases can kfilter into the lamp casing where they might come in touch with contact sparks..

This security and control of'thereliability is obtained, according "to the invention, which relatesto a lampfor lighting containers filled with .explosive gases or liquids, by composing the rlarnpof two compressed -f air chambers communicating the one with'.

- the other by a tube,"oneA chamber serving to accommodate the bulb with holder, cap and wire guard, the other compressed air chamber. containing a switch to be operated by compressed air and designed to close the circuit for the bulb so ,that in 'both compressed air chambers and in the cap exists continually similar overpressure and if any leakage occurs, the circuit will beI vautomatically cut out by outowing of compressed air, Vwhereby any danger of explosion is avoided. 3o Two embodiments of. the invention are panying drawingV in which' Fig. 1 is a longitudinal section, showing theelectric lamp with cut-out circuit to be iwliich communicates with the cha1nber"1,' a

connected to an existing cable.

Fig. 2 is a similar view, partly in'eleva-l tion,`the contact being closed anda battery used as source of current. 1

Fig. 3 showsthe'lamp contact on larger.

40 scale in section. f.

Fig. shows on smaller scale the electric lamp in elevation.`

The lamp, according to the invention, consists of a'compressed air chamber 1 and-of a compressed air chamber 2, connected the one with the other by' a tube 3. In the chamber 2 the holder 4 withy a bulb and a cap 6 are mounted, the latter being directly connected to the chamberg2 which communicates with the chamberl by channel 7 land serves for accommodating a switch .to4 be vtact pin 11, 'said piston adapted .to be.- shifted .in itslcylinder 8 bythe pressure inthe chamf :ber lnzoppstor; thefatonsrring .10 so that the contac pin 11`r campenetrate sulated so that the circuiti for the bulb l is .'closed, lThe ,circuitsis vformedby; alea d .11 vand;alears 15,516,151@ lead 15- bein'g? Cdnfnected1t o th'econtact sleeve 13 andthelead -nect'ed to the one polecfA the bulb `f5 and j the'lea'd `16to theothergpoleof ythe same.

yserves further to pack the chamberl against yand'cap.-l v l#In order-tovr prevent filtering ofexplosive 4,gases -intogthecontact sleeve -13 arranged [outside the-compressed .air chainber.i1, this trolled .by .springs ,ZLbeing shifbly. ehrjranged in saidhollow contact screws20 so operatedby compressed air and consisting,

.i1-1, the formpfconstruction sho wn, .of-:a

. ..55 sulating' jmaterial so that i-it lis insulated vagainst all other elements o f: the lamp.A yIn cylinder 8 -mounted in a partition finthe cylinder 8 `a pistonv 12 is arranged iscontroll'edV by a springlOand vhas a coninto a 'contact sleev lfwhiclri'salsov in- Theother'endsof theleads 1 4 and laare x connected to a source 'of current.,

The partitionA 9 oinsulating material thelouter air.

saidf-partitionkserves foradmttng the :Compressed f air nto the c liamberpl',v tube channels 7., chamber 2 'sleevell .isairtightly closedbya hood 18 packing 19 being interposed 3;. v "The VAleads 14,1 16 vhave, hollow4 contact nected tothe-'bulbi .Contact pinsf22 Yc onthat they can engage f withv contact! projec In order to ensure proper contact between thev .movable pins; 2 2 andathe-j projections 23 at the insertion of the bulb, the foot 24 carries a ring 25, a projection 26 of which en# gages with the holder Llfagainst which the ring is pressed by a cap Vnut 27. f The ring 25serves therefore at the same 'time' fo r }0`0 l y Y 1,765,900

' centering the bulb V5 and for fixing the same Von the holder 4. l Y

' The form of Construction shown in Fig. l -2'is desgnedfor ysuch cases ,where nosta- 5 tion'arycable exists, so that a separate source of current has to ybe used. With this olo-V Vject inview a 4battery 28vis mountyedin an upwardly directed extensionof the hood' 18 which' is airtightly packed by a screw4 cap '10 The Vcap 6 isfeiiclosed by"V a wire cage 30 Y fand the Casing of the chamloersv-l`1f andpQ, as Y w'ell asthe hood 18a-re enclosed by insu- 1 Y latingprotecting envelopesil. A, i 15 To use thelamp compressed air is forced through the; check Valveil? into Chamber l,

tube ychaber Zand through thechau'els v f 1 v7 into-the'c'ap As'sooii as the pressure hasattained apredete'rmined degree the pis'- o ton f12wis' pushed upwardjiii the cylinder 8V agaiilstV the'actiol'i ofvsprihg"V 10" so ythat the Y contact pin lllengage's'withthe Contact i Y Circuitv is closed Kand sleeve e 13, i whereby 'theV "thebulb lighted.v Y ,v f 725 'If any leakage'foccursthe compressed air has the tendency' to esc'ap'e through the l salue e Vso that-surroundiri'gexplosive gases are kept Y `away from the leakygvpoiht a'ndrcan 'not l jpenetiateintotlie ehember'e.; Y 30 As' 'soon as th'fpfes'sure in thejchambers decreases the spring y10 pushes lback the pisf "ton 123i)l thatthe Contact pin 11 disengages from '.eleev'e 13,the circuit Y being therefore vautonatically cut-out before dangerous gases 5 can Ytouch any Contact sparks)A 'Y A Owing to thefact thatv the circuit is closed by the act-ieri of Vcompress'ed'ai'r the best control is given o that the laiiip is ready for 1 use and secure in service. Y 1.40. Ielamz-*f* il 'Y Y l v .electric lampjeomprisi-ng in; (zombilnation''witha chamber with checkvalve and vpneurriatic swtchvanvd v*with af second ehember and the lamp holder", lhollow v'Contact '"45 v screws inlsad lampkholder, springontro'lled eotact pifrs in'i'said coutactscrews, a lamp foot,Y hollow eotaetprojeotione of said lamp .foot designedltoreceivegsaid Contact pins, a l Y ririg'havliga projection adapted tocentre 5o saidholder', and asore'wl oapgfor fixing said o ring on said holder. y g l 2.V 'Auelectrielamp 'as specified iii claim 1, oemprising in oombiii a'timinl` with the upper yairtight chamberarr upwardly directed kreX-k 55 l tension of said'c'hamber an electric battery Y V in saidYextension,` anda screw cap'airtightly closing said e-:teI'1"sioI1.-I Y' y I In testi" ony whereof, sigha- Y Yture'. 

